冲压发动机补燃室旋转条件下的燃烧特性研究

【作者】 孙玉香；

【导师】 鞠玉涛；

【作者基本信息】 南京理工大学 ， 武器系统与运用工程， 2009， 硕士

【摘要】 本文利用CFD软件Fluent、采用RNGκ-ε数学模型对旋转条件下的固体火箭冲压发动机补燃室中流场的燃烧特性进行研究。由于旋转模型对补燃室真实运动情况的模拟应用还处于探索阶段,另外旋转下的冲压发动机实验技术也处于探索阶段,所以本文首先对三种不同的旋转模型进行了验证和选择,最终选择模型3作为本文计算旋转条件下冲压发动机补燃室二次燃烧效应的理论分析模型,在此基础上进行研究,得到如下研究结论：(1)模拟补燃室旋转条件下的流场特性,与非旋转条件下的补燃室流场特性相比：流场整体运动变化趋势与非旋转时的基本一致,局部存在差异；补燃室中存在三个明显的旋涡使得补燃室中的流动非常的复杂,并且在旋转条件下这三个旋涡的强度明显加强；补燃室中旋转条件下与非旋转条件下的压强分布均匀,速度变化平缓,说明旋转未对补燃室流场的宏观结构产生大的影响。同时对比研究还可以发现补燃室旋转条件下的化学燃烧反应比非旋转条件下的化学燃烧反应滞后,但反应过程中所需时间减少。(2)计算了600rpm、2400rpm、4200rpm三种转速情况下补燃室中的流场,分析了不同转速下各流场的参数变化规律,研究结果表明：转速越大,化学燃烧反应越滞后,但燃料完全燃尽位置基本一致,燃烧过程中所需补燃室长度减短；转速增加,壁面温度变化减缓；转速增加对燃烧效率的影响微小,可忽略不计。(3)模拟了旋转条件下补燃室中气固两相流场,研究了600rpm和4200rpm两种转速下补燃室中流场的结构变化情况。研究结果表明：转速增加,固体颗粒开始产生化学燃烧反应的位置逐渐靠前,但反应的中心位置却逐渐靠后；在补燃室近轴区域出现无颗粒区,这对补燃室中流场的参数分布影响非常明显,这显然是由固体粒子密度大和旋转效应造成的离心力使固体粒子沿径向运动造成的。更多还原

【Abstract】 This paper research on the combustion characteristic of flow field in secondary combustion chamber of solid ducted rocket under rotating condition, it simulated by using FLUENT calculate software and adopt RNGκ-εmathematic model. Because the application of rotating model for secondary combustion chamber activate is still under groping stage, and the experimental technology of ramjet under rotating condition is at the exploratory stage, it should be verified and then choose one of the model from three different models as the theoretical analysis model of this article, which calculate and analysis the theoretical analysis model of rotating ramjet effect on post-combustion chamber. Based on this model, the conclusion as follows:(1)Simulate the flow field characteristic of secondary combustion chamber under rotating condition and compared with the characteristic of flow field of secondary combustion chamber without rotating condition, the result shows that:changes in the overall trend of movement of flow field of the rotating condition is basically consistent with non-rotating condition,only a little place is different; there are three distinct vortex in secondary combustion chamber, the flow field in secondary combustion chamber is very complex; and those three rotating vortex are significantly strengthened under rotating conditions; distribution of pressure is uniform, those show that rotating don’t have big impact on the macro-structure of the flow field in secondary combustion chamber, and the change of velocity which is in secondary combustion chamber under the rotation or not is gentle. Through comparison we can find that Chemical combustion reaction is lager than the reaction of non-rotating condition, but the time in the stage of Chemical combustion reaction is deducted.(2)Calculate flow field which is in secondary combustion chamber at different rotating speed of 600rpm,2400rpm and 4200rpm, and analysis all the parameters under rotating conditions. The result shows that:combustion reaction is delaied when the rotating speed increase, but the fuel fully combusted position is nearly uniform. The length of secondary combustion chamber required becomes short during combustion process; When speed increasing, the change of wall temperature becomes slow, and the increase of rotating speed which can be neglected has little affect for the combustion efficiency.(3)Simulate two phase of gas-solid flow field which inside secondary combustion chamber under rotating condition; when at different speed of 600rpm and 4200rpm, research movement condition of the flow field which inside secondary combustion chamber. The result shows that:When increasing speed, the position of solid particles which started happen chemical combustion reaction have progressively higher, but the position of reaction focus is lager; there is no particles in the near-axis region zone under rotating condition, it obviously affect the distributing regularity of the parameter, and it caused by the influence of the density of solid particles and the rotation effect caused by centrifugal force which made the solid particles go along the radial movement.更多还原